The present invention concerns a current distribution circuit comprising:
a first at least DC current sinking branch, which is provided with the main current stream of a first controlled semiconductor having a first control input, PA1 a second current sinking branch connected in parallel to the series arrangement of the first current sinking branch, which second current sinking branch is provided with a second control input, and PA1 means for controlling the currents through the first and second current sinking branches, which controlling means are coupled to the first and second control inputs respectively. PA1 a first AC and DC current sinking branch, which is provided with the series arrangement of the main current stream of a first current controlled semiconductor having a first combined AC/DC current control input, and a stabilising circuit for providing a DC supply voltage, PA1 a second AC current sinking branch connected in parallel to the series arrangement of the first current sinking branch, which second current sinking branch is provided with a second AC current control input, and PA1 means for controlling said currents through the first and second current sinking branches, which controlling means are coupled to the first and second current control inputs respectively.
The present invention also concerns a telecommunication device provided with a current distribution circuit.
Such a current distribution circuit and device are known from application note ETT/AN93015 on the TEA 1093 chip. In particular this note discloses a current distribution circuit comprising:
Such a current distribution circuit is being applied in telecommunication devices, such as for example a subscriber telephone, a handsfree telephone, a facsimile, a WEB-television having a telephone card, a personal computer having a telephone card etc. Usually such telephone ICs' are capable of controlling the AC-speech signals on the telephone line to facilitate communication between the telecommunication device and a central device. Furthermore they are equipped for processing the DC-line-current from the telephone line in the first current sinking branch. The stabilising circuit provides the DC supply voltage having a relative high magnitude. Processing a necessary maximum DC-line-current in the first current sinking branch of say for example approximately 140 mA would lead to an IC having a relatively large chip area for the DC current controlled semi-conductor transistor used in that first current sinking branch, because said transistor has to have a certain limited collector/emitter voltage. This collector/emitter voltage is limited and has to be kept limited because the DC supply voltage needs to have a relative high magnitude for controlling present day telephone add-on equipment, such as handsfree facilities, extra loudspeakers, and other peripheral devices.